This section describes functions and operators for examining
and manipulating bit strings, that is values of the types
bit and bit varying.
Aside from the usual comparison operators, the operators shown in
Table
9-11 can be used. Bit string operands of &, |, and # must be of equal length. When bit shifting, the
original length of the string is preserved, as shown in the
examples.

Table 9-11. Bit String Operators

Operator

Description

Example

Result

||

concatenation

B'10001' || B'011'

10001011

&

bitwise AND

B'10001' & B'01101'

00001

|

bitwise OR

B'10001' | B'01101'

11101

#

bitwise XOR

B'10001' # B'01101'

11100

~

bitwise NOT

~ B'10001'

01110

<<

bitwise shift left

B'10001' << 3

01000

>>

bitwise shift right

B'10001' >> 2

00100

The following SQL-standard
functions work on bit strings as well as character strings:
length,
bit_length, octet_length,
position,
substring,
overlay.

The following functions work on bit strings as well as binary
strings: get_bit, set_bit. When working with a bit string,
these functions number the first (leftmost) bit of the string as
bit 0.

In addition, it is possible to cast integral values to and
from type bit. Some examples:

Note that casting to just "bit"
means casting to bit(1), and so will
deliver only the least significant bit of the integer.

Note: Prior to PostgreSQL 8.0, casting an integer to
bit(n) would copy the leftmost
n bits of the integer, whereas now
it copies the rightmost n bits.
Also, casting an integer to a bit string width wider than the
integer itself will sign-extend on the left.